Suspension liner systems are widely used in prosthetic systems for residual limbs in order to stabilize soft tissue, minimize pistoning or stretching, assist circulation of the residual limb and add comfort.
Various solutions are found in the prior art, including those described in U.S. Pat. No. 7,025,793, granted on Apr. 11, 2006, and U.S. Pat. No. 8,034,120, granted on Oct. 11, 2011, both of which are incorporated herein by reference. According to these publications, a liner includes a liner body and a seal component located at the distal end area of the liner body. The seal component is flexible so it can conform to the shape of the residual limb and the internal wall of the prosthetic socket, thereby providing an airtight seal. The seal component minimizes movement of the limb within the socket, so as to prevent pistoning and rotation. In operation, the residual limb is stepped into the socket and expels air through a distal valve on the socket so as to create hypobaric suction below the seal component.
Some users find that known liners having sealing means fail to sufficiently tolerate volume fluctuations, and may leave pressure marks on the residual limb after periods of sustained use. Additional improvements may be required for some users in that known liners do not adequately conform to the user's anatomy, and therefore fail to provide necessary comfort and skin protection. Moreover, as with all suspension liners having sealing means, it is necessary that the liner provides reliable suspension after an initial phase of volume and shape conditioning after the liner is donned on the user's residual limb.